So, free means not best?
First off, you need to THOROUGHLY explain what is "best" to you:
How you are going to use it?
What OS support do you need?
What file formats and codecs do you need supported?
Are you playing/mixing multiple tracks?
Do you need to cue up a play list?
Do you need a customizable user interface?
Are you using a professional sound card? If so, what type?
And anything else you think will help explain "best". . .